Standing along International Drive outside the Orange County Convention and Civic Center, a small band of activists held signs attacking the nation's largest automaker. ''GM - Stop the Cruelty,'' one poster said.

Nearby, auto enthusiasts poured into the convention center's parking lot for the International Auto Show.

The protest is part of an ongoing effort to halt GM's use of animals in auto safety tests. GM, the only American automaker openly conducting animal tests, argues the tests are necessary to develop safer cars.

The tests, conducted since at least the 1950s, once involved monkeys, dogs and other animals, but are now limited to rats, mice, pigs and ferrets, a GM spokesman said. Today, all of the animals are anesthetized and used only in lab experiments, not actual crash tests, the spokesman said.

''Other automakers don't test with animals because we do it for them,'' said Donald Postma, the director of public affairs for GM's technical staff. ''The cost of this kind of testing is very, very expensive. Years ago, we gained a leadership role in this, and the other companies kind of got out of it.''

Each year, the company kills about 500 mice and rats, 30 to 40 ferrets and about ''a half dozen'' pigs, testing exhaust fumes on the rodents and the effects of a sudden impact on the ferrets and pigs, Postma said. The results are made public in scientific journals, he said.

But animal activists question the value of animal testing, pointing to high death rates in four GM cars listed in a recent Insurance Institute for Highway Safety report.

''If animal tests really protected people, then GM cars would be the safest on the market, and they're not,'' said Sue Santoro, president of Voices for Animals of Central Florida Inc. ''The fact seems to remain that everything they're doing hasn't made their cars any safer.''

Santoro and other animal activists want GM to use actual accidents and crash dummies for research instead of animals. Postma said GM used animal testing to develop some of the most advanced crash dummies and still uses pigs to test how accurate the dummies are.